Emeritus Pope Benedict XVI actually turned 90 years old on Sunday, but because the day was Easter, his closest aide Archbishop George Gänswein announced that a “modest” celebration would be held today instead, the day that Italians observe as Pasquetta, meaning the Monday after Easter.

What “modest” means for a retired pope living on Vatican grounds, however, is a bit different than for the rest of us.

Benedict XVI passed the day in the company of his beloved 93-year-old brother, Monsignor Georg Ratzinger, as well as a small delegation from his native Bavaria in southern Germany. Among other things, the party enjoyed some beer and pretzels, both considered staples of Bavarian cuisine.

The emeritus pope today lives in a former monastery within the Vatican, called the Mater Ecclesiae, which was created by St. John Paul II as a residence for cloistered nuns who would pray for the intentions of the papacy.

On April 12, Pope Francis visited his predecessor to wish him a happy birthday. The Vatican stamp and coin office also celebrated the pope emeritus’s birthday with the release of stamps marking important events in the life of the church spanning almost 2,000 years.

In a recent interview with the Italian newspaper Il Messaggero, Gänswein said that as he turns 90, Benedict occasionally talks about the prospect of death, but it’s not an “obsession” for him.

“I can say that he’s a serene person,” Gänswein said. “He has a soul at peace, and a happy heart.”

These days, Gänswein said, Benedict can no longer see out of one eye, although that’s an old problem, and also has difficulties walking, but otherwise is in good health.

“Certainly, he’s a man who by now is old,” Gänswein said. “It’s tough on him to walk, and he uses a walker. He can’t work on scientific texts like he used to do, but he still writes, and a lot. He has an enormous amount of correspondence from all over the world. He gets books, essays and letters, and he replies. Naturally that takes time and effort, but he thinks about every response, it’s never something done casually.”

Gänswein also said that for Benedict now, his most important activity is prayer.

“He’s convinced that prayer is apostolate number one,” he said. “Through prayer, he feels able to be close to the faithful.”

Joseph Ratzinger, the future Pope Benedict XVI, was born on April 16, 1927, which was Holy Saturday, in a small Bavarian town called Marktl-am-Inn, just across the border from Austria and the city that enchanted his youth, Salzburg. He was baptized with the newly blessed Easter water in the town’s small parish church, to parents named Joseph and Mary.

In his 1998 autobiography, published in English as Milestones, the future pope wrote that his birth and baptism on the vigil of Easter was, for him, a symbol of the human condition in its “not quite” relation to Easter and the resurrection.